THE NERVOUS SYSTEM :5ul
phrenic nerve gets sympathetic filaments. (6) The ansa hypoglossi supplies the sterno-mastoid.
The phrenic nerve (P.X. arises in the Chimpanzee from C3 and C4, from C3, C4 and Co. or from O2-C5. In the Orang and Gibbon it springs from C4 and Co ; and in the Gorilla it arises from C3 and C4, or from C3, C4 ana Co. In the Gorilla it receives sympathetic filaments, The course and relations are as in llan.
No filaments run through the caval opening in the diaphragm in the Gorilla (Eisier1. It communicates with the phrenic plexus of the sympathetic.
FIG. 55.—The brachial plexus in the Chimpanzee. Letters explained
THE BEACHIAL PLEXUS.
In all the Apes the plexus is formed by the anterior divisions of the fifth, sixth, seventh and eighth cervical and first dorsal nerves. The nerves may unite to form